1. Field of the Invention
The present invention relates to an endoscope including an operation mechanism provided on an operation portion, the operation mechanism causing an action portion of an insertion portion to act.
2. Description of the Related Art
In recent years, insertion devices, such as endoscopes, have been widely used in a medical field and an industrial field.
In the endoscope used in the medical field, an elongated insertion portion can be inserted into a body cavity that is a subject to thereby observe an organ in the body cavity, and a treatment instrument inserted into an insertion channel of a treatment instrument included in the endoscope can be used as necessary to perform various treatments.
In the endoscope used in the industrial field, an elongated insertion portion of the endoscope can be inserted into an object, such as a jet engine or a pipe in a factory, to perform inspections, such as observation and various treatments of a scar, corrosion and the like of a region to be inspected in the object.
Here, a configuration in which the insertion portion of the endoscope inserted into the subject of the endoscope is provided with an action portion, such as a bending portion bendable in a plurality of directions, is well-known.
The bending portion improves progress of the insertion portion in a curve portion in a conduit and allows changing an observation direction of an observation optical system provided on a distal end portion positioned on a distal end side of the bending portion in an insertion direction (hereinafter, simply called a distal end side) in the insertion portion.
Usually, a plurality of bending pieces are linked in the insertion direction of the insertion portion, and the bending portion provided on the insertion portion of the endoscope can be bent in four vertical and horizontal directions, for example.
One of wires that are four long members inserted into the insertion portion in which a distal end in the insertion direction (hereinafter, simply called a distal end) is fixed to a bending piece positioned closest to the distal end among the bending pieces is pulled by a bending operation apparatus that is an operation mechanism of the insertion device provided on the operation portion, and the bending portion is bendable in any of the vertical and horizontal directions.
More specifically, in the bending portion, a turn knob for vertical bending operation provided on the operation portion is turned to turn a sprocket for vertical bending that is a turn body provided on the operation portion through a turning axis for vertical bending. One of an upper side chain region and a lower side chain region of a vertical bending chain member that is a long member wound around the sprocket is pulled. One of an upper side wire and a lower side wire is pulled. The upper side wire is a long member in which a proximal end in the insertion direction (hereinafter, simply called a proximal end) is connected to a distal end of the upper side chain region through a connection piece, and a distal end is connected to the bending piece. A proximal end of the lower side wire is connected to a distal end of the lower side chain region through a connection piece, and a distal end is connected to the bending piece. In this way, the bending portion is bent in one of an upper direction and a lower direction.
Furthermore, in the bending portion, a turn knob for horizontal bending operation provided on the operation portion is turned to turn a sprocket for horizontal bending that is a turn body provided on the operation portion through a turning axis for horizontal bending. One of a left side chain region and a right side chain region of a horizontal bending chain member that is a long member wound around the sprocket is pulled. One of a left side wire and a right side wire is pulled. A proximal end of the left side wire is connected to a distal end of the left side chain region through a connection piece, and a distal end is connected to the bending piece. A proximal end of the right side wire is connected to a distal end of the right side chain region through a connection piece, and a distal end is connected to the bending piece. In this way, the bending portion is bent in one of a left direction and a right direction.
The turning axis for horizontal bending on which the sprocket for horizontal bending and the turn knob for horizontal bending are fixed is pivotably supported by a frame body fixed in the operation portion and extending in the insertion direction. Note that the turning axis for vertical bending on which the turn knob for vertical bending is fixed is covered by a circumference of the turning axis for horizontal bending.
The frame body is formed in a thin plate shape from a metallic member. The frame body functions as a member configured to position various components provided in the operation portion and resist tensile force acting back and forth in the insertion direction of the operation portion when a grasping portion is fixed to an operation portion main body of the operation portion. The frame body also functions as a so-called bottom board in which the proximal end of the insertion portion is fixed on the distal end side.
On one surface of the frame body, a first surface of a chain separator that is a guide member with a cross shape in cross section configured to separate the upper side chain region, the lower side chain region, the left side chain region, and the right side chain region to avoid interference with each other and guide the regions back and forth in the insertion direction is also fixed by screws or the like.
Note that the chain separator is formed in a cross shape in cross section, and four insertion paths of the respective chain regions are formed on the chain separator. The respective chain regions are individually inserted into the insertion paths, and the chain separator prevents the interference among the respective chain regions.
In a state that the respective chain regions are inserted into the respective insertion paths, the vertical bending chain member and the horizontal bending chain member are positioned to overlap in a height direction in which the chain separator overlaps with the frame body.
More specifically, the upper side chain region and the right side chain region are positioned to overlap, and the lower side chain region and the left side chain region are positioned to overlap. That is, one of the upper side chain region and the lower side chain region and the left side chain region and the right side chain region comes into contact with one surface of the frame body.
A chain cover that is a plate-like member is placed on a second surface on an opposite side of the first surface in the height direction of the chain separator. The chain cover guides the back and forth movement of the upper side chain region and the lower side chain region in the insertion direction and prevents the upper side chain region and the lower side chain region from dropping out from the insertion path in the height direction when, for example, the left side chain region and the right side chain region come into touch with one surface of the frame body, and the upper side chain region and the lower side chain region are positioned closer to the second surface than the left side chain region and the right side chain region in the height direction.
Note that when a plurality of holes and the like are formed on the frame body, the left side chain region and the right side chain region moving back and forth in the insertion direction may be caught by the holes and the like. Therefore, to guide the back and forth movement of the left side chain region and the right side chain region in the insertion direction, a chain cover may also be provided and placed between the first surface of the chain separator and the frame body, in addition to the chain cover placed on the second surface.
Note that the chain cover placed on the second surface of the chain separator will be called a second chain cover, and the chain cover positioned and placed between the frame body and the chain separator will be called a first chain cover.
In Japanese Patent Application Laid-Open Publication No. 2001-46329, a configuration of fixing the second chain cover to the frame body by screws is disclosed.
More specifically, Japanese Patent Application Laid-Open Publication No. 2001-46329 discloses a configuration, in which through holes into which screws are inserted are provided at intermediate positions of the chain separator and the second chain cover in the insertion direction, wherein the positions do not overlap with the respective insertion paths, and the positions protrude outside in a width direction orthogonal to the insertion direction and the height direction. Screw holes are provided on the frame body, and screws inserted into the respective through holes are screwed to the screw holes of the frame body to thereby fix the second chain cover to the frame body through the chain separator.
Note that a configuration of providing a spacer configured to fill a gap between the through holes of the chain separator and the through holes of the second chain cover in the height direction is also well-known.
According to the configurations, not only the second chain cover can be surely fixed by screws, but the fixation of the second chain cover by screws can also prevent deflection of the second chain cover formed from a thin-plate resin caused by weights of the upper side chain region and the lower side chain region downward in a direction of gravity, even when, for example, the second chain cover is formed from a thin-plate resin, and the second chain cover is positioned on a lower side in the direction of gravity due to a change in posture of the operation portion.
Note that the fixation configuration of the second chain cover described above may also be used for the fixation of the first chain cover. That is, through holes into which screws are inserted may be provided on the first chain cover.